Household freezers have become generally commonplace in the homes of individuals who desire to have relatively large volumes of food readily available. These food supplies are maintained in the household freezer at below-freezing temperatures for preventing spoilage.
One of the problems associated with these freezers was that the freezer door was sometimes accidentally left open which resulted in thawing and spoilage of the food. This often resulted in the loss of several hundred dollars worth of meat and vegetables.
In order to correct this problem, alarm systems were associated with the freezer and delivered a signal if the freezer door was left open. Delay devices were also associated with the alarm system which delayed actuation of the alarm for a preselected period of time. This permitted an individual to open the freezer door, retrieve a package of food and close the door without sounding of the door-open alarm.
However, these alarm systems generated another problem. For the user who needed to keep the freezer door open for extended periods of time for loading the freezer, cleaning the freezer, or performing other door-open operations, the sounding of the alarm while he performed these operations was exceedingly annoying.
In order to solve this problem, alarm system shutoff apparatus was provided. This permitted the user to deactivate the alarm system during periods when he expected to have the freezer door open for periods of time in excess of the alarm delay period.
These mechanical switches, as shown in the alarm systems of U.S. Pat. No. 3,100,383-Foster et al and U.S. Pat. No. 2,410,310-Smith et al, introduced an additional problem. Sometimes the user would mechanically deactivate the alarm system with the switch and then forget to reactivate the alarm system after he had finished his door-open operations. The user could subsequently fail to close the freezer door after recovering a food item and, since the alarm was deactivated by the switch, no alarm would be sounded to inform him of his mistake.
The invention therefore resides in an alarm system of a household freezer which is automatically reset in response to closing the door of the freezer.